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March 28, 2011 -- An extra dose of the stress hormone cortisol may help reduce stress-inducing phobias like the fear of heights, a study shows.

Cortisol is a hormone released by the brain in response to stress and has long been thought to play a role in memory and learning.

In the study, people who received a dose of cortisol before undergoing behavioral therapy to combat their fear of heights were more successful in eventually calming their fear.

The findings are published in the Proceedings of the National Academy of Sciences.

Retraining the Brain

Researchers say phobias are thought to be the result of an enhanced or excessive fear response to a particular stimulus, such as height, water, or spiders.

Exposure-based behavioral therapies are commonly used to help people with phobias overcome or lessen their fear responses by repeatedly exposing them to the stimulus under controlled circumstances, which allows them to make new, non-fearful associations with it. This process is called extinction learning.

“Considering the importance of extinction learning for exposure therapy, pharmacological interventions aimed at enhancing extinction processes are promising approaches to enhance exposure therapy,” write researcher Dominique J.-F. de Quervain of the University of Basel, Switzerland, and colleagues in the Proceedings of the National Academy of Sciences.

Effects of Cortisol

In the study, researchers looked at the effects of taking cortisol prior to three sessions of exposure therapy in 40 people being treated for a fear of heights (acrophobia). The participants were randomly divided into two groups. Half received 20 milligrams of the stress hormone in a pill and half received a placebo an hour before each therapy session.

During each session, the participants used a virtual-reality setup that simulated an outdoor elevator ride.

Researchers followed up with the participants three to five days after their last treatment session and again one month later.

The results showed that those who received cortisol had less acute anxiety during a virtual exposure to a phobic situation and a smaller increase in skin conductance, which is an indicator of whether a fear phobia has been overcome.

Researchers say the results may help them develop better treatments for phobias as well as a variety of anxiety disorders.

SOURCES:de Quervain, D. Proceedings of the National Academy of Sciences, March 28, 2011, online advance edition.News release, National Academy of Sciences.